The invention relates to a disc saw blade.
Hydraulic cutter blades or crosscut chain saws are currently used for various crosscutting purposes within the forestry industry, for example for units mounted in the crane end of harvesters, forwarders, excavators or suitable machines of other types. A great problem with crosscut chain saws is the difficulty of cutting several small trees simultaneously without breaking the saw bar and the chain. It is therefore desirable to use a disc saw blade instead, which works considerably faster than both the hydraulic cutter blade and the crosscut chain saw, as the trees are cut using the same working method as with a conventional clearing saw. By this means, it is possible, for example, to fell fuel wood in neglected clearing areas and to carry out roadside visibility clearance and clearing of power line paths, etc, in an efficient way. Conventional disc saw blades have as a rule, however, fixed or removable cutting edges of hard metal. A disadvantage of this type of disc saw blade is that it must be dismantled and sent to be repaired after it has hit a stone.
If, instead, a disc is used that has a standard saw chain tensioned around its circumference, a plurality of advantages are obtained in comparison to conventional disc saw blades. There has been strong competition between different manufacturers in the development of saw chains with the result that saw chains offer good value for money. A stone-damaged chain can be replaced by a newly-sharpened chain in just a few minutes. Electrical chain sharpeners, both manual and automatic, are already to be found at the premises of most forestry contractors and power saw workshops. It is therefore possible to keep chains sharpened at a low cost, which, in addition to better functioning, also reduces the power requirement of the machine. A disc saw blade of this type is described in U.S. Pat. No. 4,627,322. The disc saw blade described in this patent document is provided with a saw chain tensioned around a plate device. The plate device is designed with a first and a second plate and the chain is guided via its driving links in a chain groove that is delimited peripherally between the plates. The chain is held in the chain groove by frictional engagement between the driving links and the interconnected plates.
A disadvantage of this previously-known disc saw blade is that changing the chain is relatively time-consuming and can require access to special tools, as the plates in the plate device must be dismantled in order to release the chain. This work can be difficult to carry out in a workplace that is outdoors and exposed to wind and rain. In addition, in certain cases it can be necessary for the chain to be tensioned with a special chain tensioner that weakens the chain.
An object of the invention is therefore to achieve a disc saw blade that can be kept sharpened by simple conventional measures in a more cost-effective way than was previously the case.